1. Field
This disclosure relates to dye-sensitized solar cell. More specifically, this document is related to high-efficiency dye-sensitized solar cell and a manufacturing method for the same.
2. Description of the Related Art
Research is being conducted in for a substitute for fossil fuels to resolve the imminent energy crisis. In particular, to substitute for oil resources which may be exhausted in a few decades, researchers are focusing on how to utilize natural energy resources such as wind, atomic, and solar energy.
Different from the other potential substitutes, a solar cell is eco-friendly and makes use of unlimited solar energy. The solar cell is, therefore, receiving wide-acceptance since the development of Si solar cell at 1983, particularly due to the recent energy crisis.
However, the manufacturing cost of a silicon solar cell is high due to severe international competition caused by a demand and supply problem of Si raw material. To resolve the problem, many research organizations domestic or foreign proposed self-rescue plans. Still, difficulties remain to actually perform the plans. One of the alternative solutions to resolve the serious energy crisis is a dye-sensitized solar cell; ever since a research team headed by Dr. Micheal Graetzel of EPFL, Swiss has developed the dye-sensitized solar cell in 1991, the academic society has paid much attention thereto and many research organizations have been conducting research for the dye-sensitized solar cell.
Different from silicon-based solar cell, the dye-sensitized solar cell is an opto-electrochemical solar cell whose primary ingredients comprise photosensitive dye molecules that can generate electron-hole pairs by absorbing visible light and transition metal oxide that transfers the generated electrons. A dye-sensitized solar cell utilizing nano-particle titanium oxide is regarded as a typical research outcome among the previous research works for dye-sensitized solar cell.
Manufacturing cost of a dye-sensitized solar cell is lower than the conventional silicon solar cell. What is more, a dye-sensitized solar cell can be used for the windows of outer walls of a building or a glasshouse due to the transparent electrodes thereof. More research is needed, however, because of the low photoelectric conversion efficiency.
The photoelectric conversion efficiency of a solar cell is proportional to the number of electrons generated by absorption of sunlight. To increase the efficiency, therefore, increasing the number of electrons generated by increasing the amount of dye absorbed by titanium oxide nano-particles, increasing absorption of sunlight, and preventing generated excited-electrons from being annihilated from electron-hole recombination are required.
To increase the rate of dye absorption for a unit area, particles of oxide semiconductor are required to be fabricated in a nanometer scale. To that end, a manufacturing method of increasing reflectivity of platinum electrodes to facilitate absorption of sunlight or a method of mixing the particles with optical scattering material made from oxide semiconductor has been developed.
The previous methods, however, have revealed limitation to increasing the photoelectric conversion efficiency. Accordingly, development of a new technology for enhancing the efficiency is highly demanded.